The study from the title is indeed just a correlation, from the abstract:
"This study used a retrospective, observational analysis of deidentified tests performed at a national clinical laboratory."
Whenever you see a "retrospective, observational" related to anything having to do with medicine or biology, consider that the experts seldom see that as a proof of anything, but only a hint to a possible hypothesis that could be investigated in some other way (and then confirmed or rejected).
As another example that correlation doesn't mean causation, even if the paper is published about the correlation, see:
That "bald men and Covid-19" study did not control for age (where the older people are more probable to be both more bald and have worse outcome, making correlation not saying much when that is not controlled for), this study seems didn't control for "staying inside most of the day" or even "inside with more people" etc. Good catch.
"This study used a retrospective, observational analysis of deidentified tests performed at a national clinical laboratory."
Whenever you see a "retrospective, observational" related to anything having to do with medicine or biology, consider that the experts seldom see that as a proof of anything, but only a hint to a possible hypothesis that could be investigated in some other way (and then confirmed or rejected).
As another example that correlation doesn't mean causation, even if the paper is published about the correlation, see:
https://youtu.be/UHDi6tNMHyU?t=2780
That "bald men and Covid-19" study did not control for age (where the older people are more probable to be both more bald and have worse outcome, making correlation not saying much when that is not controlled for), this study seems didn't control for "staying inside most of the day" or even "inside with more people" etc. Good catch.